During completion operations, the completion/production equipments like packers, production tubings, valves, various sensors or measuring apparatuses, etc. . . . are installed downhole. Subsequently, production operations can begin. It is known to deploy permanent sensors for measuring various parameter related to the reservoir, the borehole, the fluid flowing into the borehole, etc. . . . These sensors are used to monitor the downhole reservoir zones and control the production of hydrocarbon. Such monitoring of the production enables enhancing hydrocarbon recovery factor from reservoir by taking appropriate action, for example by isolating a zone excessively producing water compared to hydrocarbon fluid.
Typically, the sensors measure parameters of the fluid circulating inside the borehole (cased or uncased).
Such sensors do not allow a direct measurement of the contribution of each zone forming a reservoir. To the contrary, they scan the full borehole. As a consequence, such sensors have a large investigation depth. As another consequence, it is not possible to directly measure the flow contribution of a given zone. The contribution of a particular zone is determined by performing measurements related to fluid flowing inside the full borehole volume/section and comparing it to measurements performed in the adjacent zones, for example the upstream zones.
Further, in-situ downhole calibrations are difficult to implement and thus rarely applied as they would require shutting off the whole well production.
Such sensors cannot be intrusive, namely protruding inside the well bore because this may hinder or render impossible well interventions.
Such sensors have to be suitable for slow moving and segregated fluids often encountered in horizontal section of wells.
Such sensors are not adapted to several sizes of wellbore. Indeed, there isn't a unique sensor design fitting the various configurations encountered downhole.
Therefore, theses sensors are expensive. As a consequence, the number of zones that can be instrumented is limited.
Formation testing apparatus and method are known from U.S. Pat. No. 6,047,239. The apparatus and method enable obtaining samples of pristine formation or formation fluid, using a work string designed for performing other downhole work such as drilling, work-over operations, or re-entry operations. An extendable element extends against the formation wall to obtain the pristine formation or fluid sample. While the test tool is in standby condition, the extendable element is withdrawn within the work string, protected by other structure from damage during operation of the work string. The apparatus is used to sense or sample downhole conditions while using a work string, and the measurements or samples taken can be used to adjust working fluid properties without withdrawing the work string from the bore hole. When the extendable element is a packer, the apparatus can be used to prevent a kick from reaching the surface, adjust the density of the drilling fluid, and thereafter continuing use of the work string. Such apparatus and method are not adapted for permanent monitoring application of producing hydrocarbon well.